Multifunctional composite designs for structural energy storage

Structural batteries have emerged as a promising alternative to address the limitations inherent in conventional battery technologies. They offer the potential to integrate energy storage functionalities into stationary constructions as well as mobile vehicles/planes. The development of multifunctional composites presents an effective avenue to realize the structural plus concept, thereby mitigating inert weight while enhancing energy storage performance beyond the material level, extending to cell- and system-level attributes. Specifically, multifunctional composites within structural batteries can serve the dual roles of functional composite electrodes for charge storage and structural composites for mechanical load-bearing. However, the implementation of these multifunctional composites faces a notable challenge in simultaneously realizing mechanical properties and energy storage performance due to the unstable interfaces. In this review, we first introduce recent research developments pertaining to electrodes, electrolytes, separators, and interface engineering, all tailored to structure plus composites for structure batteries. Then, we summarize the mechanical and electrochemical characterizations in this context. We also discuss the reinforced multifunctional composites for different structures and battery configurations and conclude with a perspective on future opportunities. The knowledge synthesized in this review contributes to the realization of efficient and durable energy storage systems seamlessly integrated into structural components.